Disposable syringe



Dec. 8, 1953 G. M. HlcKEY 2,661,740

DISPOSABLE SYRINGE Filed Feb. 7, 1952 Patented Dec. 8, 1953 UNITED STATES Y PATENT Y OFFICE VDISPOSBLE SYRINGE George M. Hickey, Paoli, Pa., assigner to J. lBishop & Co. Platinum Works, Malvern, ,-Pa., a corpo- -ration of Pennsylvania Application February 7, 1952, ser-famo. 270,427 .2 Claims. (Cl. 12s- 218) This invention relates to a so-called disposable hypodermic syringe and is concerned with the provision of a simple construction which permits a degree of tolerance in the size of certain of the parts thereby simplifying and lreducing the cost of manufacture. A further primary object ofthe invention is to provide a syringe construction which positively positions the needle hub in each of the two positions which it occupies when in storage and in use and further provides means whereby the two positions may be determined by the sense of touch.

The invention will be more fully described with reference to the accompanying drawings which show one illustrative embodiment of the invention.

Referring to the drawings: y

Fig, l is an axial section, partly in elevation of the assembled parts of the syringe in their inactive positions;

Fig. 2 is a similar axial section, partly in elevation, of the assembled parts of the syringe in the positions which they occupy when the syringe is ready to be used for making an injection;

Fig. 3 is an elevation of the piston which serves to eject the contents of the syringe;

Fig. 4 is an axial section of the syringe barrel;

Fig. 5 is an axial section of the perforatable plug or stopper;

Fig. 6 is an axial section of the piston rod or handle (see Fig. 2) which serves also (see Fig. l) as a protecting cap for the needle; and

Fig. '7 is an axial section of the needle and its hub.

The barrel I is made of glass or other suitable material and is cylindrical to permit the sliding movement of the piston 2 excepting that the left hand end is iiared to provide the divergent liange 3 which serves to facilitate introduction of the piston 2 and as a linger grip and the right hand end is provided with the inturned ilange or shoulder 4, the purpose and utility of which will be more fully described hereinafter.

The piston 2 is of wel1 known construction, preferably having a rigid core (not shown) covered by a rubber sleeve having several exible ridges 5 which give fluid tight contact with the inner surface of the barrel I. The piston 2 comprises the screw threaded stud 6 which may be integral with the core referred to above and serves for the attachment of the piston rod or handle 1.

The plug 8 is made of rubber or similar flexible and compressible, inert and impervious material. Plug 8 comprises the cylindrical body portion 9 and the slightly larger ange In separated by the external groove I I and is provided with the large cylindrical bore or cavity I2 and the smaller-bore I3 which extends from the bottom of the bore I2 nearly through the plug leaving -only the thin layer I4 to be punctured by the needle. The handle 1 comprises the cylindrical end I-5 .provided with the screw threaded bore vI 6 adapted to engage thestudl of the piston 2, the slightly flared or conical end I8 having the tapered smoothbcre I9 adapted to receive theinjection end 2B of Ythe needle and to engage the frustoconical end portion '2I of the needle hub, and the ange v2'2 which provides a nger grip. 'The needle assembly consists of the cannula 23 and thehub 24. The cannula consists of .theinjection end Z referred to above, Ythe puncturing endA 25, and of -course theintermedi'ate portion which'is surrounded bythe hub '215.V vThe hub 24 consists of 'the frustoconical end 2| referred to above, the flange 26 "which provides ...a nger grip and the'cylin'drical -po'rtion2'l provided with the'two spajc'ed'afpait parallel ridgesZB a'nd'i29.

The syringe is assembled and operated as follows. The plug 8 is inserted in its end of the barrel I. It will be noted that the plug 8 is iirmly anchoredto the barrel by the cooperation of the ange 4 and the groove Il. This is important because otherwise the plug might be forced inwardly into the barrel when the needle assembly is inserted. The needle assembly is then inserted into the bore I2 until the ridge 28 meets the resistance of the relatively thin layer of rubber opposite the fiange 4. This positions the puncturing end 25 of the cannula with respect to the layer I4. The barrel is then filled with the liquid to be injected and the piston 2 inserted with the aid of the handle l. The handle is then removed from the piston 2 and applied as a cap over the injection end 20 of the needle as appears in Fig. l. When the syringe is to be used the puncturing end 25 of the needle is forced through the plug 8 and the ridge 23 is forced past the ange 4 and the flange 26 is seated on the plug 8 by pushing on the handle 1 and its lia-nge 22. The handle is then removed from the injection end 29 of the needle and screwed on to the stud 6 of the piston 2 as shown in Fig. 2. At this point the syringe is ready for an injection.

It will be noted that the syringe construction has only two screw threaded parts, i. e. the bore I6 in the handle 'I and the stud 6 of the piston 2. These parts suitably are made of metal or plastic and do not involve any difficulties in their manufacture. The cannula is of course made of metal be made .to accurate size without difficulty. The body I with its ilanges 3 and 4 preferably is made of glass and here some tolerance as to size is desirable. This tolerance is provided by the rubber ridged piston 2 and the rubber plug 8. The hub 24 of the needle may be inserted into the bore l2 of the plug vregardless of considerable variation in the size of the bore I2 and of the flange .4 and nevertheless, when readied for an injection by forcing the ridge 28 past the flange 4, is securely held. Screw threading of the socket I2 in the plug 8 and of the needle hub 24 is thus avoided and no twisting operation is required for puncturing the plug.

The insertion of the needle assembly to its inactive position shown in Fig. 1 and its movement to active position shown in Fig. 2 both may be determined by the sense of touch. The resistance to further movement which occurs when the ridge 2B approaches the iiange 4 serves to advise the operator that the needle assembly has reached the limit of its inactiveposition and the sudden variation in resistance to movement as the ridge 28 passes the flange 4 serves to advise the operator that the needle assembly has arrived at its operating position.

I claim: l

1. A hypodermic syringe comprising a rigid cylindrical barrel having an inturned flange at one end thereof, a piston slidable in said barrel, said piston having a screw threaded stud projecting from one end thereof, a flexible cylindrical plug having an external groove, said plug being secured in one end of said barrel by the co-,action of said inturned flange and said groove; said plug having also a cylindrical bore, a needle assembly comprising a cannula having an injection'end, a, perforating end and a hub therebetween, said hub comprising a tapered portion adjacent the injection end and a cylindrical por-` tion adjacent the perforating end of said cannula and a flange therebetween, said cylindrical por- 4 tion of the needle hub being of substantially the same size as said cylindrical bore in said plug and having at least one circular ridge thereon adapted to engage the Wall of said bore, and a, handle member having a bore in one end adapted to enclose the injection end of said cannula and to engage the frusto-conical portion of said hub and a threaded bore in the other end adapted to engage the threaded stud on said. piston.

2. A hypoderxnic syringe comprising a hollow cylindrical body, a flexible plug and a needle assembly, said body having an integral inturned iiange at one end thereof, said plug having a cylindrical portion adapted to t the cylindrical inner surface of said body, a flange adapted to engage the end of said body, a circumferential groove adapted to iit said inturned flange and a cylindrical axial bore extending inwardly from the ange end thereof, said needle assembly comprising a cannula and ahuh secured intermediate the ends thereof, said cannula having an injection end and a perforating end, said hub having a cylindrical portion adapted to iit said bore and spaced apart parallel ridges adapted to deforrn the Wall of said bore, said ridges being of such ex ternal diameter with respect to the internal diameter of said inturned flange that extra force is required when inserting the cylindrical portion of said hub into said bore to push one of said ridges past said iiange.

GEORGE M. HICKEY.

References Cited in the iile of this patent UNITED STATES PATENTS 

